Hot-rolled strip intended for the production of non-grain oriented electrical sheet and a method for the production thereof

Abstract

The present invention relates to a hot-rolled steel strip for further processing to form non-grain oriented electrical sheet with the following composition (in % by weight) C: <0.02%, Mn: ≦1.2%, Si: 0.1-4.4%, Al 0.1-4.4%, wherein the sum formed from the Si content and twice the Al content is <5%, P: <0.15%, Sn: ≦0.20%, Sb: ≦0.20%, the remainder iron and unavoidable impurities, with a strip thickness which is at most 1.8 mm, and with a partially softened structure which is characterised by a high intensity for the α fibre (fibre representation of orientation distribution functions) in the region of 0° to 60°, wherein the ratio I 112 /I 001 formed from the intensity I 112 of the position (112) <110> to the intensity I 001 of the position (001) <110> is >0.4 and the ratio I 111 /I 001 formed from the intensity I 111 of the position (111) <110> to the intensity I 001 of the position (001) <110> is >0.2.

1. A method for producing a hot strip
 the method comprising the following working steps: 
 melting a steel with the following composition in % by weight: 
 C: <0.02% 
 Mn: ≦1.2% 
 Si: 0.1-4.4% 
 Al: 0.1-4.4%; wherein the sum formed from the Si content and twice the Al content is <5%, 
 P: <0.15% 
 Sn: ≦0.20% 
 Sb: ≦0.20%, 
 the remainder iron and unavoidable impurities, to form a steel melt; 
 casting the steel melt to form thin slabs; 
 continuous hot-rolling the thin slabs at a temperature of the thin slabs following the casting of the steel, the continuous hot rolling comprising a plurality of passes; and 
 wherein at least one pass of the hot-rolling is carried out at temperatures at which the hot strip consists of an austenitic structure, and a plurality of subsequent passes of the hot-rolling are carried out at temperatures in which the hot strip consists of a ferritic structure. 
 
     
     
       2. The method of  claim 1 , wherein the phosphorous content in the hot strip is <0.08% by weight. 
     
     
       3. The method of  claim 1 , wherein the degree of total deformation achieved during the hot-rolling is at least 90%. 
     
     
       4. A method for producing a hot strip
 the method comprising the following working steps: 
 melting a steel with the following composition in % by weight: 
 C: <0.02% 
 Mn: ≦1.2% 
 Si: 0.1-4.4% 
 Al: 0.1-4.4%; wherein the sum formed from the Si content and twice the Al content is <5%, 
 P: <0.15% 
 Sn: ≦0.20% 
 Sb: ≦0.20%, 
 the remainder iron and unavoidable impurities, to form a steel melt; 
 casting the steel melt to form a thin strip; 
 continuous hot-rolling following the casting of the steel in one or more passes; and 
 wherein at least one pass of the hot-rolling is carried out at temperatures at which the hot strip consists of an austenitic structure, and a plurality of subsequent passes of the hot-rolling are carried out at temperatures in which the hot strip consists of a ferritic structure. 
 
     
     
       5. The method of  claim 1 , wherein the temperature during hot-rolling is less than 850° C. 
     
     
       6. The method of  claim 1 , further comprising carrying out with lubrication at least the last hot rolling pass during the hot rolling step is at a temperature within the ferrite region. 
     
     
       7. A method for producing non-grain oriented electrical sheet from a hot strip comprising the following composition in % by weight:
 C: <0.02% 
 Mn: <1.2% 
 Si: 0.1-4.4% 
 Al: 0.1-4.4%; wherein the sum formed from the Si content and twice the Al content is <5% 
 P: <0.15% 
 Sn: ≦0.20% 
 Sb: ≦0.20% 
 the remainder iron and unavoidable impurities, 
 with a strip thickness which is at most 1.8 mm, and with a partially softened structure which is characterized by a high intensity of an orientation density in the region of 0° to 60°, wherein the ratio I 112 /I 001  formed from the intensity I 112  of the position (112) <110> to the intensity I 001  of the position (001) <110> is >0.4 and the ratio I 111 /I 001  formed from the intensity I 111  of the position (111) <110> to the intensity I 001  of the position (001) <110> is >0.2 and produced according to  claim 4 , further comprising the following working steps: 
 pickling or annealing and pickling of the hot strip; 
 cold-rolling of the hot strip; 
 intermediate annealing of the cold strip; and 
 final annealing or annealing with subsequent deformation with a total degree of deformation of less than 20%. 
 
     
     
       8. The method of  claim 7 , further comprising carrying out the cold rolling in at least two stages with an intermediate annealing.